Burke: Arnica ovata vs. Arnica rydbergii

	Arnica ovata	Arnica rydbergii
	sticky arnica, sticky-leaf arnica	Rydberg's arnica, subalpine arnica, subalpine leopardbane
Habit	Perennial from a freely rooting rhizome, the stems solitary or tufted, 1.5-4 dm. tall.	Perennial from short, scaly rhizomes, the stems clustered, 1-3 dm. tall.
Leaves	Cauline leaves 3-4 pairs, mostly sessile, ovate to deltoid or elliptic, irregularly toothed, the middle ones the largest, with blades 4-8 cm. long and 2-6 cm. wide.	Basal leaves petiolate, oblanceolate, 3- to 5-nerved, frequently on separate short shoots; cauline leaves opposite, 3-4 pairs, oblanceolate to lanceolate, 3- to 5-nerved, concentrated on the lower part of the stem, 3-10 cm. long and 5-25 mm. wide.
Flowers	Heads generally several, narrow, with few disk flowers; involucre 10-14 mm. high with pointed bracts, covered with stalked glands; rays about 8 or about 13, 1.5-2 cm. long; pappus straw-colored, sub-plumose.	Heads solitary or few, top-shaped; involucre 9-13 mm. high, its bracts pointed, glandular on the back with hairs on the margins; rays about 8, yellow, pistillate, 1-2 cm. long; disk flowers yellow, perfect; pappus white, barbellate.
Fruits	Achene.	Achene densely covered throughout with short, soft hairs

	Arnica ovata	Arnica rydbergii
Flowering time	July-September	June-August
Habitat	Rocky places from middle elevations to the subalpine and alpine.	Dry meadows and open slopes at high elevations in the mountains.
Distribution	Occurring on both sides of the Cascades crest in Washington; Alaska to California, east to Montana and Utah. [WildflowerSearch map] [BONAP county map]	Occurring on both sides of the Cascades crest in Washington; British Columbia to northern California, east to Alberta and Colorado. [WildflowerSearch map] [BONAP county map]
Origin	Native	Native
Conservation status	Not of concern	Not of concern
Sibling taxa	A. chamissonis, A. cordifolia, A. discoidea, A. fulgens, A. gracilis, A. lanceolata, A. latifolia, A. longifolia, A. mollis, A. nevadensis, A. parryi, A. rydbergii, A. sororia	A. chamissonis, A. cordifolia, A. discoidea, A. fulgens, A. gracilis, A. lanceolata, A. latifolia, A. longifolia, A. mollis, A. nevadensis, A. ovata, A. parryi, A. sororia
Web links	Local floras: BC, CA, OR, WA Local Web sites: CalFlora, CalPhotos, Flora NW, PNW Herbaria WildflowerSearch iNaturalist (observations) USDA Plants Database LBJ Wildflower Center SEINet Plants of the World Online Encyclopedia of Life Wikipedia Google Image Search	Local floras: BC, OR, WA Local Web sites: Flora NW, PNW Herbaria WildflowerSearch iNaturalist (observations) USDA Plants Database LBJ Wildflower Center SEINet Plants of the World Online Encyclopedia of Life Wikipedia Google Image Search

Arnica ovata

Arnica rydbergii

sticky arnica, sticky-leaf arnica

Rydberg's arnica, subalpine arnica, subalpine leopardbane

Habit

Perennial from a freely rooting rhizome, the stems solitary or tufted, 1.5-4 dm. tall.

Perennial from short, scaly rhizomes, the stems clustered, 1-3 dm. tall.

Leaves

Cauline leaves 3-4 pairs, mostly sessile, ovate to deltoid or elliptic, irregularly toothed, the middle ones the largest, with blades 4-8 cm. long and 2-6 cm. wide.

Basal leaves petiolate, oblanceolate, 3- to 5-nerved, frequently on separate short shoots;

cauline leaves opposite, 3-4 pairs, oblanceolate to lanceolate, 3- to 5-nerved, concentrated on the lower part of the stem, 3-10 cm. long and 5-25 mm. wide.

Flowers

Heads generally several, narrow, with few disk flowers;

involucre 10-14 mm. high with pointed bracts, covered with stalked glands;

rays about 8 or about 13, 1.5-2 cm. long;

pappus straw-colored, sub-plumose.

Heads solitary or few, top-shaped;

involucre 9-13 mm. high, its bracts pointed, glandular on the back with hairs on the margins;

rays about 8, yellow, pistillate, 1-2 cm. long;

disk flowers yellow, perfect;

pappus white, barbellate.

Fruits

Achene.